From German Patent Disclosure DE 41 15 119 A1, EPE, describes a watertight electrical plug connection that comprises a plug and a counterpart plug associated with it; it is known to provide receiving chambers in the plug into each of which one contact element, connected to an electric line, is inserted in a disconnectably locked fashion. In the inserted state of the plug connection, to a contact part of the counterpart plug is connected to the contact element.
A packing element, formed as an O-ring, is supported on the plug, spatially separated from the contact elements in a circumferential groove thereof, and when the plug is put together with the counterpart plug, this O-ring rests on an inside face of the counterpart plug that partially encloses the plug and closes the plug connection at this coupling point.
In the presence of accelerations acting upon the plug connection, for instance in the form of shaking motions in operation of a Diesel engine, when the plug is in the plugged-in state, relative motions arise between the contact element and the contact part that is inserted with force in the contact segment formed on the end of the contact element, since the contact element is unsupported by the packing element and the connecting point between the contact element and the contact part can vibrate transversely to the longitudinal direction of these contact members in the context of lateral play in the receiving chamber. As a result, the touching surfaces of the contact element and contact part can rub against one another, and contact is then made via the less-well contacting carrier material of the contact element and contact part, thus impairing the reliability of the contact of the plug connection.